Brand new builder in need of some info/assistance...... / Tesla Coils / Forums

Forums

4hv.org :: Forums :: Tesla Coils

« Previous topic | Next topic »

Brand new builder in need of some info/assistance......

1 2 next

Move Thread

LAN_403

Kokamo

Wed Oct 21 2009, 03:07AM

Registered Member #2442 Joined: Wed Oct 21 2009, 02:09AM
Location: Liberty Hill, Texas
Posts: 6

Gentlemen, you guys have a wonderful site here, LOTS to read.

Ok, strait out....honestly....I'm new to this. Not gonna lie. I understand that electricity is a cool and deadly thing. I am super careful around this stuff as I have lots of experience with your regular home woreing and that sort of voltage.

I've been all over the net looking at and studying TC for about 2 weeks. There is soooo much to know about these things, it gets really overwhelming. I understand how a TC works, but it's the little things that matter is what I am having difficulty learning. So here I am asking for some help.

Things I am having trouble understanding......

~How to match the primary coil to the secondary coil
~How to measure Uf and/or Khz
~How to choose capacitors (I made some saltwater capacitors) and how to test them to be sure they are working
~And finally, how to test my transformer.

I have a mini TC built. It's a basic simple design built from stuff laying around the house. (I'll go get some pics after I post this)

Things that I know....

High Voltage: Franceformer (kv @30ma <~~~about 90% sure it's not working properly....need to know how to test it
Primary: #10 solid core copper wire wrapped around a 2" tube.... tapped once every turn or so wrapped about 13 times.
Secondary: 1" PVC wrapped in #30...about 7" tall and about 600ish turns (I'll go count)
Capacitors: 4 saltwater filled coke bottles wrapped in foil (not entirely sure I built them correctly)
Toroid: 1-1/2" aluminum duct in a small 6" circle

Spark gap is minuscule......like .005". Anything much larger and it will not spark.

I get absolutely no sparks. I can use the earth ground and drag out a 3/4"ish spark, but no streamers of any kind.

Honestly, I think I should try a known good transformer before I start much more troubleshooting. How can I test the one I have?

I'll try and get pics as soon as I can. Remember, this is a very small and very crude setup. I'll clean it up later once I get it working.

Thanks guys,

~Joe

klugesmith

Wed Oct 21 2009, 04:12AM

Registered Member #2099 Joined: Wed Apr 29 2009, 12:22AM
Location: Los Altos, California
Posts: 1716

Welcome, Joe, and thanks for the complimentary words about 4hv.
Learn to use the advanced search feature here. A quick scan of posts with the words Testing and Transformer rapidly turns up:

Read ALL of that post and all of the thread it explicitly mentions.

Kokamo

Wed Oct 21 2009, 04:46AM

Registered Member #2442 Joined: Wed Oct 21 2009, 02:09AM
Location: Liberty Hill, Texas
Posts: 6

Thank you Kluges. Really nice post. I should have searched for some of the simpler things like testing the coil, but I really don't know what to "search" for when it comes to measuring capacitance and so fourth.

BTW, I did the test to my NST and it is a goner. No workie like it's "said" to. Gonna have to find a good one and then test it out. But it does have enough juice to make a few sparks and enough to light up a flourecent from about 8" away.

Here are those pics I promised......

klugesmith

Wed Oct 21 2009, 05:08AM

Registered Member #2099 Joined: Wed Apr 29 2009, 12:22AM
Location: Los Altos, California
Posts: 1716

Kokamo wrote ...
BTW, I did the test to my NST and it is a goner. No workie like it's "said" to. Gonna have to find a good one and then test it out.

The popular wisdom here is that a tesla coil can turn a good NST into a bad one if you don't have a protective filter circuit.

A -very- simple NST test is to take flexible wire with one end solidly connected to metal case of transformer -- e.g. tightened screw not just alligator clip. Manipulating other end with an insulating stick, bring it close to each HV terminal in turn & see how long an arc you can draw. Won't be much with NST ground fault protection, a feature to prevent fires.

In which time zone do you live? (e.g. in case someone here wants to offer you a NST)

Thanks for the illustrations. But go easy on big pictures esp. when new here -- official width limit is 400 pixels.

-Rich

Kokamo

Wed Oct 21 2009, 05:35AM

Registered Member #2442 Joined: Wed Oct 21 2009, 02:09AM
Location: Liberty Hill, Texas
Posts: 6

Rich, thanks for the tip on the filter. I did not know that. I will need to research that and have that done before the new NST goes on the table.

Question, when you say it won't have much of an arc with a ground fault protection....how do I know if it has this? It's the round small leg on the 110 plug right? Thats usually the ground and it does have that. I did an arc test off the case. One lead will give a 1...maybe 2mm arc and the other will give nothing. It just kinda sparks when you touch the case. You arc them together it actually does slightly better...maybe a 1/16th of an inch. So I'd say it's no good.

As far as the band width, I didn't think that was associated with images hosted on another site. Lol....I have been wrong once before. If it is a problem, I will re-size them if needed. My apologies.

Again, thanks for your help,

~Joe

BTW....I am at -6....central....Austin, Texas to be exact.

Proud Mary

Wed Oct 21 2009, 06:21AM

Registered Member #543 Joined: Tue Feb 20 2007, 04:26PM
Location: UK
Posts: 4992

Kokamo wrote ...

. If it is a problem, I will re-size them if needed. My apologies.

Hi Joe, and welcome to the wonderful world of 4HV.org!

We run a pretty tight ship here to keep up the quality,
so I'm sure you'll understand if I ask you to reduce your
images to 400 pixels or less in width.

It's always a good idea to read the site rules so as not to
jeopardize your chances of a flying start!

best wishes,

Harry.
Moderator

Steve Conner

Wed Oct 21 2009, 09:20AM

Registered Member #30 Joined: Fri Feb 03 2006, 10:52AM
Location: Glasgow, Scotland
Posts: 6706

Yep, the 400 pixels width limit has nothing to do with bandwidth. It's to preserve readability of the forum for folks with smaller screens. If you want to post big images, you can attach them to your post, and the forum software will convert them to clickable thumbnails. Which actually conserves bandwidth too.

Dr. Dark Current

Wed Oct 21 2009, 10:22AM

Registered Member #152 Joined: Sun Feb 12 2006, 03:36PM
Location: Czech Rep.
Posts: 3384

Sorry don't have the time to read the whole thread, but it seems you had the capacitor in parallel with your NST? If so, it's no wonder it got fried. You must have the spark gap in parallel to your transformer and the cap with the primary in series.

Kokamo

Wed Oct 21 2009, 04:21PM

Registered Member #2442 Joined: Wed Oct 21 2009, 02:09AM
Location: Liberty Hill, Texas
Posts: 6

Steve McConner wrote ...

Yep, the 400 pixels width limit has nothing to do with bandwidth. It's to preserve readability of the forum for folks with smaller screens. If you want to post big images, you can attach them to your post, and the forum software will convert them to clickable thumbnails. Which actually conserves bandwidth too.

Fixed it up Steve, thanks for the info.

Dr. Kilovolt wrote ...

Sorry don't have the time to read the whole thread, but it seems you had the capacitor in parallel with your NST? If so, it's no wonder it got fried. You must have the spark gap in parallel to your transformer and the cap with the primary in series.

Dr. Kilovolt, take a look at THIS PIC. This is exactly how I have it wired up. Is it in parallel? The only changes I have made from the diagram is that I am using only one bottle cap as the other ones I built don't seem to work.....well, all 4 of them don't work as good as the one you see in the pictures above.

Also, the NST was a unit I picked up at a garage sale. It was tested on a neon light and worked, but when it's hooked up to a neon light, it still works to this very second.

Herr Zapp

Wed Oct 21 2009, 04:30PM

Registered Member #480 Joined: Thu Jul 06 2006, 07:08PM
Location: North America
Posts: 644

Kokamo -

Since your coil IS generating at least a meager output, your NST can't be completely dead. Before assuming that a defective transformer is the root cause of your coil's poor performance, let's start to compile some specific data that will help determine what is wrong. You'r transformer could be fine, and your problems could be caused by an "out-of-tune" condition, or some other issue.

1. What is the output voltage of your NST? (your first post omitted this information)
2. What were the results of your "testing" for output (arc length) from each of the NST's two output leads?
3. Did you use any kind of Tesla coil design program to determine the physical and electrical parameters for your primary, secondary, topload, and tank capacitor? If you didn't use a TC design program, how did you determine the required values?
4. Do you know the capacitance value (either measured or calculated) of your salt-water capacitor bank?
5. What is the resonant frequency (either measured or calculated) of your Tesla coil?
6. Please provide a schematic or sketch for your coil, showing how you have everything is connected together.

(You DO understand that the fundamental requirement for Tesla coil operation is resonance, where the primary and secondary circuits are "tuned" to oscillate at exactly the same frequency? If you don't know the answers to questions #3-5, then you probably don't really understand how a Tesla coil operates, and need do do some research.)

So, let's start with the basics, and work through your coil's design, construction and tuning one step at a time.

Dr. Kilovolt -

What leads you to believe that Kokamo has his tank cap in parallel with his NST?

Regards,
Herr Zapp

1 2 next

Moderator(s): Chris Russell, Noelle, Alex, Tesladownunder, Dave Marshall, Dave Billington, Bjørn, Steve Conner, Wolfram, Kizmo, Mads Barnkob